In the past year our core has assisted 11 NHLBI investigators in 19 transgenic and knockout projects. Eight of these projects have been successfully completed, and 11 projects are still ongoing. In addition, our core is always trying to reach out to NHLBI scientists to offer any assistance using our special equipment or expertise. Because of the enormous potential of induced pluripotent stem cells (iPSC) to improve human health and our expertise in embryonic stem (ES) cell culture and embryonic micro-manipulation, we recently started to explore iPSC technology for expanding our services. Presently, we are capable of deriving mouse iPS cell lines, and is working on the derivation of human iPSCs. We will closely interact with other NHLBI laboratories/cores that are also interested in iPSCs, and try to complement rather than direct repeat their strategies and methods. Our strength lies in our capability of performing microinjection for introducing cells back into early embryos for assessing pluripotency and differentiation propensity, and our extensive experience in gene-targeting. This later skill will allow us not only to knockin reporter (such as GFP or lacZ) or selection marker (such as neo or puro) into specific genomic loci to aid the enrichment of specific differentiation lineages, but also in the long run to correct genetic defects of patient-derived iPSCs. In addition, we have devoted a small portion of our effort and resources to research, which, at the present time, is to characterize a dwarf and obese mouse line generated in our facility using the gene-trapping method.